Process of fixing nitrogen



. uct. 6, 1925. 1,356,202

J. C. CLANCY Bxocass of* FIXING NITROGEN Filed July 18, 1922 20 heretofore suggested compr'ses success or .eremo monomer;

Application le Telly lil, lehrt.

To' all whom it may G01/Loom: v

Be it known that l, Josef@ Cremer: a citizen of the United States, residing et 416 vWest 215th Street,inthe'couuty or ilew e York emi vStute of ller@T York, have invented certain new and useful lmprovements in Processes of Firing Nitrogen, 'of which the following is e specification.,

This invention relates tothe lisation of l atmospheric nitrogen in the form oil alkali metal eysnifls, l Many processes have been suggested 'for the lisation of nitrogen involving the pro- .cluctiou of alkali vmetal cyeniels. @ne of such processes comprises passing hriqucttes formed of e mixture ofthe carbonate or hydrete or" en, alkali motel, carbon, and iron through e highly heated furnace in en etniosphere of nitrogen. Another process heating certeit: nitride such es titanium nitricl and silicon .nitriolin admixture with carbon and alkaliv metal compound .such as sodium ce"honste in the presence of. nitrogen. ln

both olf-"these processes it has been recog nizetl thlt the nitrogen eut-ers into chemical combine-tion vmore reet-lily et e lower temfif'jwre when a metal catalyst is present in'. elle, action Y\.1}ii: ;ture However, the

eboveiuentionecluid other similar processes heretofore suggested sult'er from the clilll! culties involved in the recovery el the formeel oyenirl from the re product, i fit-is this connection that aside. from the unconvertecl sodiuinrurhonate, unconsumeelcerhor. and. secondary products in the reaction mixture there .is slee present the metal catalyst which must not only be sepe- J rated lfrom the cyaniel product but also7 for 40 economical operation, must he recovered and returned to the process.

An object of my invention is e process for the xation of nitrogen in the :torre oI' cyanifl in which some of the ohgectioneble features of prior processes avoided.

My process broadly comprises reacting upon en eikeli-bescsupplyng materiel in molten or iiuicl condition 'with nitrogen and e, cerhoueceous gasi the presence of e solid The process, more specilicelly, characterized byI the toet that" the molten -alkalihase-supplying material and. the ges mess, including atmospheric nitrogen and e gaseous carboneceous compound, ere couteetw i inlet on to a tower filling .10000 C. or higher.

ed with .each other in e reaction VZone or chamber in the presence of anal iu contact with solid messes of e catalytic material which retain their physical form and position and serre not only es the cetelyst for the reaction, but also supporting und distributing pecking units vfor the contacting molten alkali metal compound incl the gas mess.` rlhe process is further characterized hy the fact ltheittlie nitrogen iixing reaction -is eliecterl in e. reaction .Zone or chamber to which the molten alkali compountlis supM plico' through a. trapped inlet and from which the .molten reaction product is discharged through a, trapped outlet, the gas entering into the reaction and the gaseous reaction products being supplied. to and evithtlrawn from the reaction member respectively Without interruption of or interterence with the continuity enel. estehlishecl reacting conditions of the process. Still a further characteristic ol the process resides in theuse ot e furnace heated directly or in.

part directly hy the passage of electrical current through the catalytic material, the lutter serving; es the conductor andy resistor for the current. 'This feature of heating the 'furnace by 'means of electric current passed through the cetelytic mess While affording :i method otsecuring` the desired high tein-A perature, uniform hestno; end accurate temper'. ur., control, pret rshly is combined with e vpi eliminury or suppleu'ientel heating oi the reagents supplier? to the rreaction chamber by oi' heet derived from the burning ot' luel. Flirt'y 'features oi the iu'- vention will appear hereinafter as the invention is described in detail.

Fused sodium carbon-etc (socle ash) is feti into :i closecl furnace shaft tllrough e sealed oi" y packing units l cya iid in the resulting n'iolten A prouct is low.

producer the furnace operated at a temperature higher than would be most economical.

the upper end of the furnace shaft is an outlet tor Waste gases and gaseous reaction products. Molten soda ash and the gas mass comprising nitrogen and a hydrocarbon are continuously supplied to the furnace shaft at the top and bottom respectively and gases and molten reaction products are Withdrawn Jfrom the furnace shaft at the top and bottom respectively, the tem perature of the furnace' being maintained and controlled by the passage of electric current through the porous or permeable mass o catalytic packing units. l

Sodium carbonate or soda ash is the preferred alkali-basesupplyingr agent employed in the process principally because it gives satisfactory results and is inexpensive. instead oi sodium carbonate l may employ other alkali metal carbonates such as potassium carbonate, or the alkali metal oxids or hydroxide or bicarbonates and perhaps other alkali met-al compounds or mixtures of a plurality of different compounds of one or more alkali metals.

Atmospheric nitrogen is the logical nitrogenous gas for use in the process.

The carbonaceous gas may be either saturated or unsaturated hydrocarbons or mixA tures thereof of Widely diil'erent boiling points. Among the carbonaceous materials which may be used'are the hydrocarbons ot the paraffin series such as natural gas, methane, gases obtained by the distillation and by cracking petroleum oils, vapors or" crude petroleum, kerosene vapors and coke. oven gas. The preference with regard to the carbonaceous gas employed will depend upon the cost of the supply of the carbonaceous gas in the particular locality in which the process is carried out. For instance. in the neighborhood ot natural gas fields, natural gas may be the least expensive gas, `While in another locality an inexpensive supply .of colte oven ons mi l,sight be available, and in an oil field the use ot petroleum vapors ll'roducer gas may be employed but its use is not desirable When the process is oiieratcd For the purpose of producing), c vanid heraus(z the cyanid formed ijnthe 'upper part olf the raction zone is decomposed liv the carbon rncnoliid component of the prfalucer fas in the lower' part of the reaction zone and the yield oi reaction lllhcu it is desired to usc s a y 'around 12500 C., whereby the bulli of the lili cya-.nid formed volatilixcd and pa, es from cyanid may be recovered as :sich om erably is converted to ari-annua and other ol" f the nitrogen compounds by irl/fm. gases with steam.

` @n the other han-"i,

out

tilizcd incassa dueelammonia the -Furnace is operated at the high temperature stated 'for the purpose of volatilizing the cyanide and the use of producer gas then comes into the economical consideration. [lilith regard to the catalytic material for the process I have discovered that there are a great variety ot' materials which may be used and there are :1 number of Ways oi' forming and haudlinsf the catalytic material. The catalytic nuiterial serves two purposes in the process, iirst, it promotes the nitrogen ixinzcr reaction and second, it serves as a distributing;` contact surface for the reacting materials. The catalytic material must therefore be a material which promotes the nitrogen iixing reaction, and it must be capable of wiillstanding the high temperature and the action of the reacting materials without Vfusion or disintegration.

In general, l have found that the metal nitrids, carhids, and c:u'l.io-uitrids which have the necessary high melting points and which may be formed at relatively low teniperaturcs 'from the metals or their alloys or their compounds such as, their oxide or natural ores, by thc action ot' a cyanid or other nitrii'ying agent or by the action Of nitrogen and active carbon in the presence of an alkali metal compound are catalytic agents suitable for use in my process.

The catalytic material is employed in the physical forni of packing units ci either irregular or regular shapes which may be associated as a packing material in either a promiscuous or a symmetrical arrangement.

The packing units may be 'formed Wholly of one catalytic material or a mixture oi' two or more catalytic materials or Ythey may comprise one or more ot the catalytic Inaterials mixed with or bonded by other noncatalytic substances. or the units may be initially 'formed of material capable of being converted to catalytic niateriah For instance, the units may be formed or moulded from a single metal in mass or an alloy of two or more metals capable ot' forming the high melting point carbide.. nitrids or carbonitrids, or the units may be `initially formed oi an alloy oi a catalyst-'lormind metal with another non-catalystdiorniin'g metal. Ur the units may initially formed oi mixtures oi' one or more catalystforming metals or 'their alloys in Vfinely divided torni bonded with inert materials. The units may also be iniien-- nase-,aca

or the catalytic agent may be formed Wholly or in part by treatmnt of the units prior to their introduction into the reactor.

. Metals which l haue found to possess the required characteristics, that is, the capability of forming catalytic nit-ride, carbide and carbo-nitride having the necessary high melting 'points are chromium, mananese,I titanium, tantalum, thorium, niobium, vanadium, zirconium and uranium.

The formation of the catalytic material is illustrated-in the following examples.

Tantalum oxid or its natural ore inthe form of small lumps is subjected to the action of molten sodium cyanid at high teniperature. At about 1000o C. tantalum carbid is formed and at about 11500 C. tantaluin nitrid and carbo-nitrid are formed.

(lr the tantalum oXid 'or ore in the :term oi' lumps is treated with moltensodium carbonate and a hydrocarbon or active carbon, such as that formed by heatinga hydrocarbon to about its cracking temperature,

Aand nitrogen, the carbid being ormed at about 1000o C. and the nitrid and carbonitrid being formed at about 11500 C. ln a similar manner the oXids of thorium, chromium, manganese and titanium may be converted tothe carbids, nitrids and carbonitrids.

It will be apparent that the formati n oi the metal carbids, nitrids. and carboids by treatment with a. molten alkali metal, active carbon and nitrogen as (ascribed. above may take place ci'f'ler outside or the nitrogen fixing oaf r as a vpreiiniinaify step or in the nitro" i vng reactor, as a part off the nitrogen i'ixing; operation.

method of :forming catalytic packing units is'as toller 'lhe raw mater as the oxid or natural ore ci one or more metals such as those mentioned, pulrerieed and mixed with a suitable binder such as starch, glucose oi' a solution ol soda ash4 rlhe resultingdough is dried and baked in mass and then broken into pieces of suitable size Ifor packing units or the dough is moulded into the desired i'orm for packing units such as the so-called liaschig rings about two inches in diameter and is then dried and baked. The units so formed are then subjected to treatment with an alkali metal cyanid or with an alkali niet al compound and nitrogen and active carbon or a hydrocarbon gas as described above to convert the metal content to the -arbids, nitrids and carbo-nitrids or they may betreated Witha nitrifying agent such as ammonia.

The treatment with ammonia isillustrated as follows. l grind the natural ore, tantalite, Which contains about `percent of tantalum o "d and 2O to 25 percent of coA lumbium oxid to about 200 mesh, mix it to .oii ammonia.

kali metal in the nitrifying` operation witliout fusion or disintegration.k In a similar way packing units may be made from the oxids or ores oi thoriun ,I manganese, titanium and chromium.

It will be apparent that the catalytic metal carbids, nitrids, and carbo-nitrids formed by the chemical treatment described may thereafter be embodied in the form of packing units by .mixing the pulrerized material with a bin-der such as starch, glucose, .soda ash, or the like, and moulding the resulting dough and bakingit.

When the high melting point metals such as .Inanganese, chromium, titanium, tantalurn, thorium or their alloys, suoli as, ferromanganese, ferro-chromium, ferro-titanium, i'erroftantalum, nickel-chromium, ferrouraniurn, cobalt-chromium and the like metalsor alloys are used as packing units in the form of pieces or cast into forms, such as rings, it is preferred to treat the units with sodium cyanid at about 10000 C. to form a catalytic surface on said units before they are employed in the nitrogeniixing operation.

. icc

The carbid ot iron is not suitable for use in. the process when sodium carbonate is the molten alkali metal compound used because the iron carbid fuses at about 1100.0' C., and melts down in the furnace sto pping the operation ci' the process. lt may be possible to use iron carbid packinviinits in a process in Which an alkali metal compound of lower melting point, such as potassium carbonate or a mixture ot sodium and potassium carbonate is used. v

l prefer 'to form the active catalytic com pound oi? the metals, that is, the carbides or nitride or carbo-nitrids prior to beginning of the nitrogen fixing operation.

lalso prefer a mass or column of catalytic packing units comprising a plurality of layers of different catalytic materials.

Manyforms ofI apparatus may be devised for carrying out my process. yTwo forms-oit apparatus suitable tor carrying out the proc'- essl are illustrated in the accompanying drawings, in Which- Fig. l is a vertical section of my preferred form of apparatus, and

' Fig. 2 is a vertical section oia modied torni of apparatus.

Referring to Fig. l, Agis the shaft of the A observation of the reaction. products, that is,

the molten cyanid product and the gas issuing through-the 'pipe 14.` v

.The use of ordinary fuel for melting the soda ash to a temperature of 900 C. or higher,A ver substantially reduces the amount of e ectrical energy required in the processand .consequently reduces the cost of operation while at the same time permitting* the thorough and uniform and readily controlled heatinglof the catalytic filling to a suitablyl high temperature by means of Y flow over the surfaces of abody of catalytic packing units comprising independent units' electrical energy.

The use of hi h melting point catalyst for the reaction as t e supporting and .distribut-A ing packing for securing` intimate contact of the catalytic agent and the reacting ma- Pterials and also as the electrical resistor for the heating of the reaction mixture is a very important and advantageous feature of the process.

It will be apparentthat many'processes and many different forms of apparatus may` s* be devised which will fulfill the conditions .2

required in the process.

p I clalm: l .1. In a continuous .process of fixingnitrogen the step comprising, subjecting a flowing body of molten oxygen compound tie base 'ofwhich is an alkali metal, toa gas current comprising a. carbonaceous gas and nitrogen at a reacting temperature below 1200o C. and. above 800 4C. in the'presence of aY high melting point nitrogen containing body which is a solid at said temperatures and capable of reacting with alkali and carbonaceous gas to form cyanid and capable of reacting 'with nitrogen contained in the re- IS a trogen the step comprising` subjecting a flowing body of molten alkali metal compound to the'action ot a gas current com-` prising a carhonaceous gas and nitrogen in a reaction zone wherein the reactants are made to contact with packing units composed oi high melting point nitrogen containing bodies 'aplable of' both .splitting oti and combining with nitrogen atreacting temperature during the operation vof the process, supplying molten alkali metal compound to saidzone through a liquid sealed inlet. and withdrawing the molten reaction product from said zone through a. .liquid sealed outlet while maintaining said nitro- 'gen containing packing units '.n said zone.

3. The step in a continuous process of fiX- ing nitrogen as defined in claim 1. in whichV the alkali metal compound is permitted to .flow over the surfaces of a solid nitrogencontaining catalyst.

the alkali metal compound is'permittedto flow over the surfaces of a containing catalyst.

solid metal nitrid 5. The step 1 n a continuous process of fiifI ing nitrogen 4tts-defined in claim Al, in which the alkali metal compound is permittedt comprising combined .tantalum trogen. v Y 6. The step in a continuous process of fixing nitrogen as defnedin claim 1in lwhich flow over the surfaces 'of asolid catalys and bnithe alkali metal compound'is permitted to containing different catalytic ,metal compounds.

-7. The step in a continuous process of fix- 4metal compound with nitrogen and hydrocarbon at reacting temperature in contact with stationary-catalytic massesshaped vto act as supporting and distributing packingv units. y

9. The step in the process of fixing nitrogen as defined in claim 8 in `which said catalytic masses are heated by the passage of electrical current. f

10. vIn a process of fixing nitrogen the step comprising, subjecting high melting point carbo-nitrogenous bodies to the action ot a gas comprising nitrogen. hydrogen and carbon, and an alkali metal compound at a temperature sutiicient to canse the chemical combination of said alkali metal rvith carbon and nitrogen but insuiiicient to melt said carbo-nitrogenous bodies.

11. On a process ottixing vnitrogen the t step comprising. contacting vmolten alkali metal componi" i wii bonaceous gas prf of solid catalyst comprising tanti-num .ntrid at reacting temperature.

12. The step in the process of fixing nitrogen as defined in claim 11 in which said V`solid. catalyst comprises tantalum carbonitrid. Y

13. In a process offixing nitrogen the step comprising establishing andfmain'taining a counter current flow of molten alkali mctal'compo'und/and gas comprising nitrogen and a hydrocarbon through. a fixed polftrogen and a carrous catalytic body comprising separate zones containing tantalum nitrid. chromium nitrid, thorlum mtr-1d, titanium nltrld and manganese nitrid, at reacting temperature.

In testimony whereof I aflix my signature. f

JOHN CLLINS CLAN'CY. 

